More than 31 years ago my precious little son Damien fell asleep one night and never woke up again. It was three days before his second birthday. Damien had a twin sister, Charlotte, and an older brother, Alexander. Our family was bereft.
After a thorough investigation, no cause of death could be determined. He was another child who died suddenly and unexpectedly in infancy with no known cause. We were told it was Sudden Infant Death Syndrome, but in modern times this is called Sudden Infant Death Syndrome (SIDS) or Sudden Unexplained Death in Childhood (SUDC). I’ve been told that “these things happen,” that “it was tragic,” and even “to go home and have more babies.” But I could not.
As the months went by, I thought obsessively about what I must have missed. I found it unspeakably cruel that this was the only night of his short life that I slept through. You know, Charlotte, his twin sister, had very restless sleep and I got up several times throughout the night to tend to her. And since they were in cots next to each other, I usually made a little fuss over Damien. But the night he died, Charlotte hadn’t disturbed my sleep.
And then one morning, as I was sitting in the sun, a sudden thought struck me – maybe my constant disruption had kept it alive! Maybe he really couldn’t arouse properly!
My thoughts afterwards were chaotic and disorganized, but little by little I began to explore the mechanism of arousal. Although I was a lawyer at the time, I had previously trained and worked as a biochemist and was comfortable in the world of research. Through the literature, I discovered that the autonomic nervous system (ANS), and more specifically the parasympathetic nervous system (a major branch of the ANS), had been thought to play a role in SIDS, and that some believed these infants might have had an arousal deficit.
I asked many experts about a possible connection, all of whom metaphorically patted me on the head and told me to go home, stop obsessing, and have more babies. But how could I? If I had more babies, would they die too?
So while I found this observation relevant, no one else seemed to. Undeterred and spurred on by a determination I was only just discovering, I approached the senior forensic pathologist in NSW, Australia. He advised me to speak to a man at Sydney University. I did. And he listened.
As a result, I ended my legal career and my marriage, already deeply fractured by grief, which dealt the final blow to me when I returned to college. I did my PhD studying the ANS and evaluating arousal responses in infants at risk of SIDS. After several years of research, it was clear that some infants did in fact have autonomic dysfunction and an impaired arousal system, but it was unclear which part of the ANS was involved.
Unfortunately, by the time I finished my PhD, I had very little money and, having two children to raise and raise, I returned to law practice. This meant I had to put my research on hold for a while, but my obsession with SIDS has always been with me, and kids are growing up.
It’s often thought, especially by those who haven’t suffered the visceral onslaught of infant death, that there comes a time when you’re “over it.” I testify to this error. Not a day went by that I didn’t think about my son and how he died. And because I’m a biochemist, I started thinking about the chemistry of the ANS, because after all, it’s just chemistry.
To facilitate my return to research, I had built a business alongside my law practice that would give me the financial independence to resume my work, and in 2014 I did so. The intervening years had not been wasted as I had spent countless hours researching the various aspects of the ANS and in particular the cholinergic system that regulates certain brain functions such as sleep and arousal. Luckily for me, our knowledge of these systems and arousal had continued to grow over the past several years.
This meant I was well prepared when I returned, and my hypothesis was simple:
1. Autonomic dysfunction (where the ANS is not functioning properly) is implicated in the pathophysiology of sleep apnea and SIDS. Sleep apnea has also been linked to the pathophysiology of SIDS. Ergo, do infants and children who suffer from sleep apnea also have autonomic dysfunction?
2. There are two major enzymes in the cholinergic system, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and altered levels of either or both enzymes may indicate some degree of autonomic dysfunction.
The study I conducted involved conducting sleep studies and measuring the activity of these enzymes in a group of children thought to be at risk for sleep apnea. In the course of this work I found a very fascinating result. A nine-week-old baby (still alive and well four years later) was found blue and unresponsive twice over a three-day period for no apparent reason. This baby had a highly unusual and somewhat unexpected profile of these enzymes, one that had not been noticed before and one that clearly indicates lower activity of the chemical BChE. Finally this was a link I was looking for.
I took action. I had been thinking about this next step for half my adult life. My plan was to use dried bloodstains collected at birth and compare survival versus nonsurvival in the first two years of life with the aim of developing a biomarker of susceptibility to sudden death. It was a long shot, but the find was so unusual that my colleagues and I thought it was worth going down the rabbit hole. But there was not enough money for research. In order not to be deterred, I decided to crowdfund. I set this up in Damien’s honor, called it Damien’s Will, and raised the necessary $50,000.
It took another tedious four years to complete the study, including Covid lockdowns, but the work is finally done. Our study looked at 600 babies and found that there was strong evidence that lower BChE specific activity (BChEsa) was associated with death compared to groups with a “non-SIDS death”. This association was not evident in the non-SIDS group.
This is the first time we have been able to identify a potential biochemical marker before death that distinguishes SIDS babies from their matched controls or infants who die from other causes. It was a surreal moment when I first realized that. In fact, it’s still hard to believe what we’ve achieved.
While BChE-specific activity was lower on average in the SIDS infant group, it is true that there was some overlap between the low levels of BChE activity in both non-survivors and survivors, leaving much to be done . But I feel validated. My journey was extraordinarily challenging with so many hurdles. Many times I was close to giving up, but the thought of Damien and all the other babies gave me the strength to keep going. However, now I am truly excited about the future possibilities of this research and humbled by the many stories of gratitude and heartbreak that have been shared with me.
One of my hopes for this work is that it will bring some comfort to the parents who have experienced the tragedy of SIDS. Far too often they are to blame for the death of their precious child in their care. They can now have peace of mind that their child’s death was not due to a lack of care or something they failed to do.
We still have a long way to go. We haven’t found the cause, just hints at a biomarker, but this one is strong. It means that for the first time we have the ability to identify infants at risk of SIDS before they die and provide appropriate interventions. I believe that with sufficient funding we could achieve this in the next three to five years.
Carmel Harrington PhD is Executive Director of Sleep for Health and an Honorary Research Fellow at Westmead Children’s Hospital. She is a founding member of the Sleep Health Foundation and a member of the Australasian Sleep Association. You can learn more about supporting her work at Damien’s Legacy.
All views expressed in this article are the author’s own.
https://www.newsweek.com/sids-stole-my-toddler-dedicated-my-life-finding-cause-1708561 “SIDS stole my toddler. I have dedicated my life to finding its cause.